Problems That Should Be Paid Attention to when Calibrating the Touch Trigger Probe

1. The reason why the dynamic diameter of the touch trigger probe is smaller than the static diameter

After learning about the principle of probe calibration, we can easily explain why the dynamic diameter of the probe stylus is smaller than the static diameter.

(1) The touch trigger probes is equivalent to a lever structure in principle. During the touch measuring, the sensor must be able to trigger (equivalent to the switch off) in order to send out a signal. Since the probe stylus (force arm) has a certain length, after the gem ball of the probe stylus touches the standard ball, it has to travel a certain distance to trigger the sensor. The longer the probe stylus, the greater the distance. Therefore, the trigger signal is delayed, so that the diameter of the fitting ball is smaller than the sum of the diameter of the gem ball and the standard ball. When the software subtracts the diameter of the standard ball from the diameter of the fitting ball, the "dynamic diameter" of the calibrated probe stylus we get is smaller than its static diameter.

(2) The probe stylus will be slightly deformed during the touch measuring, which increases the signal delay, which is also one of the reasons for this phenomenon.

(3) The time required for the trigger signal of the sensor (probe) to reach the counter is fixed. However, the rate of change of the grating reading during this time is related to the touch speed of the measuring machine. When the touch speed is fast, the "dynamic diameter" of the probe stylus is small.

In summary, it is normal that the dynamic radius of the touch trigger probe is smaller than the static radius, so the surveyor does not need to worry about this. The calibration of the probe is an important part of the measurement process, and the deviation generated will be directly added to the measurement result. When using combined probes (multiple probe angles, multiple probe positions and multiple probe lengths), its calibration accuracy is particularly important, and we must attach great importance to it. When a problem is found, rechecking the results of the probe calibration will waste valuable time and increase a lot of work.

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